Posted by Jacquie on October 20, 2002 at 19:09:01:
ok im totally lost on how to do the following problems. ive tried to do each one but keep getting answers that are no where near what they should be. (plz include all steps if u know how to do it tnx)
1. prove the identity
tan(3pie/4 - z)= (tan z + 1)/(tan z - 1)
2. prove the identity
sin(x+y) + sin (x-y)= 2sinxcosy
3. find the value
cos(3pie/8)